Retire Exadata Express examples (oracle-samples#157)

Signed-off-by: Gerald Venzl <gerald.venzl@oracle.com>

Author: gvenzl

README.md

@@ -5,7 +5,6 @@ This repository stores a variety of examples demonstrating how to use the Oracle
 | ------------- | ------------- |
 | [db-sample-schemas](https://github.com/oracle/db-sample-schemas) | Git submodule of the Oracle Database Sample Schemas |
 | [dotnet](https://github.com/oracle/dotnet-db-samples) | .NET based examples |
-| [exadata-express](./exadata-express) | Exadata Express examples |
 | [java](./java)  | Java based examples |
 | [javascript](./javascript) | JavaScript based examples |
 | [machine-learning](./machine-learning) | Oracle Machine Learning examples |